#include <iostream>
#include <vector>

using namespace std;

//判断A,B大小，保证大减小
bool cmp(vector<int> &A, vector<int> &B){
    if(A.size() != B.size())    return A.size() > B.size();
    for(int i = A.size() - 1; i >= 0; i--){
        if(A[i] != B[i])    return A[i] > B[i];
    }
    return 1;
}

//进行减法
vector<int> sub(vector<int> &A, vector<int> &B){
    vector<int> C;
    int t = 0; //表示借位

    for(int i = 0; i < A.size(); i++){
        t = A[i] - t;
        if(i < B.size())    t -= B[i];
        C.push_back((t + 10) % 10);
        if(t < 0)   t = 1;
        else t = 0;
    }
    while(C.size() > 1 && C.back() == 0)  C.pop_back();
    return C;

}

int main(){
    string a, b;
    vector<int> A, B;

    cin >> a >> b;
    for(int i = a.size() - 1; i >= 0; i--)  A.push_back(a[i] - '0');
    for(int i = b.size() - 1; i >= 0; i--)  B.push_back(b[i] - '0');

    vector<int> C;

    if(cmp(A, B))   C = sub(A, B);
    else{
        C = sub(B, A);
        printf("-");
    }    
    for(int i = C.size() - 1; i >= 0; i--)  
            printf("%d", C[i]);  


    return 0;
}